In the foodservice area, post-mix beverage dispensers are well known which mix a concentrate or syrup with several measures of water and then dispense the mixture on demand to reconstitute a hot or cold beverage such as juice, coffee or tea. Serious sanitary problems may occur with microbiologically sensitive products such as low acid starting components that can enter into the composition of an on-demand prepared beverage. Other types of food dispensers may easily be subjected to bacterial contamination and growth such as soft ice cream serving machines.
For instance, milk is naturally a low acid fluid comprising a relatively balanced proportion of proteins, lipids and fluids with a pH of about 6.7. This formulation provides a favorable ground for critical bacterial growth. Milk can rapidly spoil when it comes into contact with contaminated moisture, dust, fluid, etc., and thus proper handling and dispensing of such a product can be challenging.
Therefore, a food dispenser handling liquid milk based components requires regular and thorough cleansing with appropriate cleansing solutions to remove food residues and control microbiological growth in the tubing and mechanical parts that are in contact with the food product, such that they are cleansed properly. If done manually, this process is very laborious, time consuming and expensive in manpower. The cleaning process requires disassembly and re-assembly of the main functional parts of the machines. For instance, employee labor required to properly clean a cappuccino delivering machine or a visual bowl dispenser requires an average of 30 minutes a day. Furthermore, neglect or error in the cleansing process may not only affect the quality of the beverage, but also lead to serious hygienic hazards.
U.S. Pat. No. 6,287,515 to Koosman et al. relates to a cleaning and sanitizing assembly for clean-in-place (“CIP”) food and beverage automatic dispensing machines. The assembly includes at least one water line and at least one sanitizer line to introduce at least one sanitizer to condition water from the at least one water line. The at least one sanitizer may be ozone generated by an ozone generator from air filtered and dried in an air filter/dryer and then added to the water in an air flow apparatus. Typically, the sanitized water is introduced into the dispensing machine through a tank which normally contains the food product mix. The sanitized water is dispersed into the tank through a rinse tube or a spray nozzle extending across the top of each reservoir. Both the rinse tube and spray nozzle may be moved away from the tank should access to the tank become necessary. A cover over the rinse tube and spray nozzle prevents splashing of the sanitized water. From the tank, the sanitized water proceeds throughout the dispensing machine to self-clean food and beverage contact surfaces. However, using an ozone generator with this system has a number of disadvantages. Ozone generators tend to be expensive and bulky. The U.S. Environmental Protection Agency has placed also strict limits on ozone concentrations in the air. Ozone can damage the lungs when inhaled. Thus, ozone devices used for purifying water need to provide protection against the ozone being released from the water and creating high local ozone concentrations in the air surrounding the dispenser. Ozone generators also require high voltage generation since they normally rely on using a corona discharge to create ozone from oxygen. As a result, safety considerations arise due to the use of high voltage. Sometimes a purified oxygen source is also required. Moreover, since ozone is very reactive, it cannot be stored in water, and must be generated on demand by the system.
U.S. Pat. No. 6,240,952 to Schroeder relates to an aseptic product dispensing system that includes a sanitary connection assembly interposed in fluid communication with a substantially conventional aseptic product source and a substantially conventional product dispenser. The sanitary connection is provided with an automated cleaning system whereby a combination of pressurized gas, flushing fluid and/or sanitizing solution may be injected into, and thereafter evacuated from, the sanitary connection assembly. A controller is connected to each source for selectively delivering the selected fluid to sanitary connection and throughout the dispenser. The selected fluid is then evacuated through the terminal valve of the dispenser. The cleaning protocol is such that water is circulated first, then a sanitized fluid is circulated and maintained for a certain time in a soak cycle. Finally, a pressurized gas is circulated to displace water and/or sanitized solution remaining in the system up to the dispensing valve. This clean-in-place system is cumbersome and complicated due to the number of sanitizing/rinsing lines and the same number of sanitizing/rinsing sources corresponding to those lines. Therefore, this system is more adapted for being installed outside and in connection with a traditional dispenser. Furthermore, the system is very much sanitizer consuming in the sense that the sanitizer flows through the dispenser and is evacuated through the dispensing valve. For reducing the volume of sanitizer flowing through the dispenser, the cleaning protocols provides a soaking cycle in which the sanitizer remains for a certain time within the system. However, in order to be effective, soaking must be maintained during several hours which means that a full cleaning protocol can only be carried out overnight.
Sanitization of food product dispensers known in the art typically takes a significant amount of time to complete. The complete rinsing and cleaning cycles including times for heating the cleaning solutions can take anywhere from 20 minutes to more than an hour for a traditional food product dispenser which is generally commercially feasible only at particular times in a day. Dispensing certain products, such as hygienically sensitive products, requires more frequent cleaning. Growth rates of microorganisms, for example, can lead to their number doubling as fast as every half hour, which can lead to unhealthy numbers of microorganisms in a matter of hours. Chemical sanitizers require full contact to the flow path and all surfaces to be cleaned.
Patent EP 0 245 641, titled “Machine for the treatment and/or the preservation of beverage or liquid or pasty food mixes”, describes a system whereby a food/beverage dispenser may be maintained in “sterile” conditions at the point whereby the dispensed product leaves the dispenser nozzle, i.e. comes into contact with the external environment.
Similarly, GB2367105, titled “Cleaning Conduits, Especially in Milk Vending Machines”, details a control system that monitors either time, volume or number of dispenses since the last cleaning operation in order to auto-initiate the next cleaning. This system, however, is not designed to fit a post-mix beverage dispenser, where milk comes not only in contact with an outlet pipe, but contacts a much more tortuous path including mixing bowl, whipper, and nozzle. GB2367105 also recommends the concurrent use of ultraviolet light for purposes of sanitization, which is impractical in a post-mix dispenser.
Therefore, there is a need for a clean-in-place system that is more convenient, less labor intensive and time consuming than in known systems that provides assurance as to the hygienic state of the dispenser.